The present invention concerns silos, more particularly to distribution devices for use with particulate material in silos.
Silos are commonplace and are used to receive and store particulate material such as silage, grain or woodchips. Generally, a silo includes a hopper, which is connected to a feeder pipe for feeding the material from a source into the silo. The material fills the silo to a predetermined level and then typically, an operator stops the operation. This operation while straightforward suffers from a number of significant drawbacks. Undesirably, particulate material tends to forms peaks as the material fills the silo. The silo""s storage space is thus used inefficiently because the area around the material peak, when the peak is at a maximum height, is left unfilled. If the material peak is left to increase in size, it will eventually block the feeder pipe. This is particularly problematic in applications that require feeding of material into the silo and then generally immediate use after filling, for example, in temporarily storing woodchips in the silo and then feeding the woodchips into a drying oven. An operation of this type normally requires continuous monitoring by an operator to turn off the feeder when the material peak reaches its maximum level.
Several distribution device designs have been made to solve the aforesaid problems, a few examples of which include:
U.S. Pat. No. 3,430,788, issued Mar. 4, 1967 to Edming for xe2x80x9cSilage Distributorxe2x80x9d;
U.S. Pat. No. 4,159,151, issued Jun. 26, 1979, to Wood for xe2x80x9cSilo Filling Apparatusxe2x80x9d;
U.S. Pat. No. 4,555,210, issued Nov. 26, 1985 to Wigram for xe2x80x9cSpreader Device in a Storage Container for Uniform Filling of the Container with Granular Goodsxe2x80x9d;
U.S. Pat. No. 4,972,884, issued Nov. 27, 1990 to Souers et al. for xe2x80x9cMethod and Apparatus for Uniformly Loading Particulate Material into, Cylindrical Bedsxe2x80x9d; and
U.S. Pat. No. 5,238,035, issued Aug. 24, 1993 to Poussin et al. for xe2x80x9cEquipment for Filling a Container with a Divided Solid Productxe2x80x9d.
The designs above, however, suffer from a number of important disadvantages. Most are of a complex design, which may not allow for retrofitting onto an existing silo. Several of the designs include rotator elements that rotate about an axis, which is axially aligned with the feeder tube. The rotator elements are often substantially smaller than the diameter of the silo and as such may not uniformly distribute the particulate material in the silo. Disadvantageously, the rotator elements do not appear to be activatable when the material begins to form the aforesaid peaks and as such would require constant monitoring by the user to prevent the feeder tube""s blockage.
Thus there is a need for an improved distribution device.
The present invention is directed towards a solution to the aforesaid problems by providing a novel parallel arrangement of an axis of rotation of a number of sweeper arms and a feeder conduit axis. Advantageously, this parallel arrangement allows particulate material that exits the feeder conduit to be captured by the sweeper arm and deposited in a uniform manner over the surface of the particulate material. This uniform distribution significantly increases the efficient use of silo storage space because the sweeper arms substantially reduce or essentially eliminate the formation of peaked material in the silo. Moreover, reduction of peak formation also reduces obstruction of the feeder conduit by the peaked material. Furthermore, a sonic sensor detects the level of the particulate material in the silo and automatically controls the sweeper arm""s rotation, thereby allowing the silo to operate essentially unattended. In addition, a frame is used to mount the sweeper arms adjacent the feeder conduit and thus is easily retrofitted onto the top of an existing silo. Also, by using the device to distribute the particulate material, its compaction in the silo is significantly reduced.
In a first aspect of the present invention, there is provided a particulate material distribution device for evenly distributing particulate material in a silo, said silo including a frame connected to a silo upper end for supporting a feeder conduit having a feeder end portion which is at least partially positioned in an open end of said silo, said feeder conduit having a feeder conduit axis which is generally parallel to a silo sidewall, said device comprises:
a rotatable sweeper arm connected to said frame and positioned generally orthogonal relative to said feeder conduit axis, said rotatable sweeper arm being at least partially positioned in said open end of said silo and spaced apart from said feeder conduit end and having a sweeper arm axis of rotation which is generally parallel to said feeder conduit axis.
Typically, the rotatable sweeper arm receives said particulate material from said feeder conduit end and sweeps said particulate material along a path of travel from said feeder conduit end towards said silo sidewall, said particulate material being evenly distributed over a surface of said particulate material adjacent said sweeper arm so that said feeder conduit end is unobstructed by said particulate material. The device typically comprises three rotatable sweeper arms. Each sweeper arm extends radially outwardly from a sweeper axle, said axle being connected to said frame.
Typically, each sweeper arm includes: an arm connector portion connected to said sweeper axle; a distal end portion; and an intermediate arm portion interconnecting said connector portion and said distal end portion. The intermediate arm portion includes: a leading wall and two trailing walls, said leading wall being generally parallel to said sweeper, axis of rotation, said trailing walls being generally horizontal.
Typically, each sweeper arm is arcuate in the direction of said rotation.
In another aspect of the first embodiment, a plurality of spaced apart arm panels are connected to said intermediate arm portion, each arm panel depending from said leading wall.
Typically, the feeder conduit axis is located generally centrally said silo, said sweeper arm axis of rotation being off-center such that said sweeper arm rotates eccentrically.
Typically, the device further comprises: a level sensor connected to said frame and in communication with said rotatable sweeper arm to provide a first signal to said sweeper arm to rotate when a first portion of said particulate material reaches a first predetermined level in said silo. The sensor provides a second signal to said sweeper arm to stop rotation when a second portion of said particulate material reaches a second predetermined level in said silo. The first portion of said particulate material is peaked. The second portion of said material is generally planar.